Computing a distributed optimal controller in which subcontrollers have access to subsets of global system information is in general a computationally intractable problem. Indeed, even when restricted to quadratic costs, Gaussian noise, and linear dynamics, the resulting optimal controller can be nonlinear and difficult to compute [1]}. Nevertheless, significant progress has been made in distributed optimal controller synthesis over the past two decades by identifying structural assumptions on the underlying dynamics and information exchange structure such that the resulting distributed controller synthesis problem is convex.
